The invention relates to communicating enhancement data associated with audio/video content in multiple layers.
Ancillary information, such as program sub-titles, emergency messages, closed caption messages, and program guide information, may be transmitted along with regular television content. More recently, other types of ancillary information that may be sent with television content include enhancement data such as web pages, multimedia information, or other digital data files. Ancillary information may be sent in the vertical blanking interval (VBI) of an analog television broadcast signal or sent with digital television content over a digital transmission transport medium.
Various standards exist that provide for transmission of ancillary information along with television content. One standard is the Advanced Television Enhancement Forum (ATVEF) Specification, Draft Version 1.1r26, dated Feb. 2, 1999. The ATVEF specification is designed to provide for transmission of enhancement data along with television content in both analog and digital systems, such as cable systems, satellite systems, terrestrial systems, and so forth.
The amount of enhancement data or other types of ancillary information that can be received by a receiving platform depends largely on its capabilities (including storage, processing, and data transfer rate capabilities, for example). Different receiving platforms may have different capabilities. For example, some relatively low-capacity receiving platforms such as earlier version set-top boxes may have a relatively low bandwidth for receiving ancillary information. To ensure receipt of ancillary information by as large an audience as possible, content creators may reduce the amount of ancillary information in a transmission to target such low-capacity receiver platforms. The assumption may be that such platforms are being used by the greatest number of viewers. Thus, the quality of, and features available in, enhancement data or other types of ancillary information may be limited to accommodate the relatively low-capacity receiving platforms. This may limit options that may be offered the audience.
In general, according to one embodiment, a method for communicating enhancement data associated with audio/video content includes receiving, in a receiver system, enhancement data. The enhancement data is associated with a plurality of alternatives each including one or more layers of enhancement data. One of the alternatives is selected based on the capacity of the receiver system, and the one or more layers associated with the selected alternative are received.
Other features and embodiments will become apparent from the following description and from the claims.